Method and apparatus for transmitting control information in a wireless communication system

ABSTRACT

A method and user equipment (UE) are provided for use in a time division duplexing (TDD)-based wireless communication system. A primary component carrier (PCC) and a secondary component carrier (SCC) are configured. The PCC and the SCC have different uplink-downlink (UL-DL) configurations. UE operations are performed under assumption that a physical downlink shared channel (PDSCH) is not received through any part of a downlink subframe in the SCC regardless of a length of a downlink pilot time slot (DwPTS) of a special subframe of the PCC, for a subframe #k where the PCC is the special subframe including the DwPTS, a guard period (GP), and an uplink pilot time slot (UpPTS), and the SCC is a downlink subframe.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. application Ser.No. 14/352,929 filed on Apr. 18, 2014 (now U.S. Pat. No. 9,300,452issued on Mar. 29, 2016), which is the National Phase ofPCT/KR2012/008648 filed on Oct. 22, 2012, which claims priority under 35U.S.C. §119(e) to U.S. Provisional Application No. 61/549,243 filed onOct. 20, 2011, U.S. Provisional Application No. 61/560,795 filed on Nov.16, 2011, U.S. Provisional Application No. 61/641,912 filed on May 3,2012, U.S. Provisional Application No. 61/696,315 filed on Sep. 4, 2012,and U.S. Provisional Application No. 61/705,133 filed on Sep. 24, 2012,all of which are hereby expressly incorporated by reference into thepresent application.

BACKGROUND OF THE INVENTION

The present invention relates to a wireless communication system and,more specifically, to a method and apparatus for transmitting/receivingcontrol information. The wireless communication system can supportcarrier aggregation.

Wireless communication systems have been widely deployed to providevarious types of communication services including voice and dataservices. In general, a wireless communication system is a multipleaccess system that supports communication among multiple users bysharing available system resources (e.g. bandwidth, transmit power,etc.) among the multiple users. The multiple access system may adopt amultiple access scheme such as Code Division Multiple Access (CDMA),Frequency Division Multiple Access (FDMA), Time Division Multiple Access(TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), or SingleCarrier Frequency Division Multiple Access (SC-FDMA).

An object of the present invention devised to solve the problem lies ina method for efficiently transmitting/receiving control information in awireless communication system and an apparatus for the same. Anotherobject of the present invention is to provide a channel format, aresource allocation scheme and a signal processing method forefficiently transmitting/receiving control information and an apparatusfor the same. Another object of the present invention is to provide amethod for efficiently allocating resources for transmitting/receivingcontrol information and an apparatus for the same.

The technical problems solved by the present invention are not limitedto the above technical problems and those skilled in the art mayunderstand other technical problems from the following description.

The object of the present invention can be achieved by providing amethod in which a UE performs communication in a time division duplexing(TDD)-based wireless communication system supporting aggregation of aplurality of CCs, the method including: performing uplink transmissionor downlink reception in each subframe on a first CC according to afirst UL-DL configuration; and performing uplink transmission ordownlink reception in each subframe on a second CC according to a secondUL-DL configuration, wherein, when a subframe configuration of the firstCC and a subframe configuration of the second CC include configurationsshown in the following table, subframe #k+1 of the second CC is set to X

Subframe #k Subframe #k + 1 First CC U D Second CC U U

wherein U denotes an uplink subframe, D denotes a downlink subframe andX denotes a subframe in which signal transmission is limited.

In another aspect of the present invention, provided herein is a UE foruse in a TDD-based wireless communication system supporting aggregationof a plurality of CCs, the UE including: a radio frequency (RF) unit;and a processor, wherein the processor is configured to perform uplinktransmission or downlink reception in each subframe on a first CCaccording to a first UL-DL configuration and to perform uplinktransmission or downlink reception in each subframe on a second CCaccording to a second UL-DL configuration, wherein, when a subframeconfiguration of the first CC and a subframe configuration of the secondCC include configurations shown in the following table, subframe #k+1 ofthe second CC is set to X

Subframe #k Subframe #k + 1 First CC U D Second CC U U

wherein U denotes an uplink subframe, D denotes a downlink subframe andX denotes a subframe in which signal transmission is limited.

In subframe #k of the second CC, signal transmission may be limited inlast M SC-FDMA (single carrier frequency division multiple access)symbols thereof and M may be an integer equal to or greater than 1.

When transmission of at least one of a PUCCH (physical uplink controlchannel) signal, a PRACH (physical random access channel) signal and anSRS (sounding reference signal) in subframe #k of the second CC isscheduled, transmission of the at least one of the signals in subframe#k of the second CC may be dropped.

The UE may operate on the assumption that a PUSCH (physical uplinkshared channel) is not allocated to subframe #k of the second CCirrespective of whether or not the PUSCH has been actually allocated tosubframe #k of the second CC.

When a PUSCH signal is transmitted in subframe #k of the second CC,information corresponding to one or more SC-FDMA symbols, included inthe PUSCH signal, may be rate-matched or punctured.

According to the present invention, it is possible to efficientlytransmit/receive control information in a wireless communication system.Furthermore, it is possible to provide a channel format, a resourceallocation scheme and a signal processing method for efficientlytransmitting/receiving control information. In addition, it is possibleto efficiently allocate resources for transmitting/receiving controlinformation.

The effects of the present invention are not limited to theabove-described effects and other effects which are not described hereinwill become apparent to those skilled in the art from the followingdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates physical channels used in a 3GPP LTE system as anexemplary wireless communication system and a signal transmission methodusing the same;

FIG. 2 illustrates a radio frame structure;

FIG. 3 illustrates a resource grid of a downlink slot;

FIG. 4 illustrates a downlink subframe structure;

FIG. 5 illustrates an uplink subframe structure;

FIG. 6 illustrates a slot level structure of PUCCH format 1a/1b;

FIG. 7 illustrates a slot level structure of PUCCH format 2/2a/2b;

FIG. 8 illustrates a CA (carrier aggregation) communication system;

FIG. 9 illustrates cross-carrier scheduling;

FIG. 10 illustrates half duplex (HD) type TDD based carrier aggregation;

FIGS. 11 and 12 illustrate subframe reconfiguration schemes according toembodiments of the present invention; and

FIG. 13 illustrates a BS and a UIE applicable to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention are applicable to a variety ofwireless access technologies such as Code Division Multiple Access(CDMA), Frequency Division Multiple Access (FDMA), Time DivisionMultiple Access (TDMA), Orthogonal Frequency Division Multiple Access(OFDMA), and Single Carrier Frequency Division Multiple Access(SC-FDMA). CDMA can be implemented as a radio technology such asUniversal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can beimplemented as a radio technology such as Global System for Mobilecommunications (GSM)/General Packet Radio Service (GPRS)/Enhanced DataRates for GSM Evolution (EDGE). OFDMA can be implemented as a radiotechnology such as Institute of Electrical and Electronics Engineers(IEEE) 802.11 (Wireless Fidelity (Wi-Fi)), IEEE 802.16 (Worldwideinteroperability for Microwave Access (WiMAX)), IEEE 802.20, and EvolvedUTRA (E-UTRA). UTRA is a part of Universal Mobile TelecommunicationsSystem (UMTS). 3^(rd) Generation Partnership Project (3GPP) Long TermEvolution (LTE) is a part of Evolved UMTS (E-UMTS) using E-UTRA,employing OFDMA for downlink and SC-FDMA for uplink. LTE-Advanced(LTE-A) is evolved from 3GPP LTE. While the following description isgiven, centering on 3GPP LTE/LTE-A for clarity, this is purely exemplaryand thus should not be construed as limiting the present invention.

In a wireless communication system, a UE receives information from a BSon downlink (DL) and transmits information to the BS on uplink (UL).Information transmitted/received between the UE and BS includes data andvarious types of control information, and various physical channels arepresent according to type/purpose of information transmitted/receivedbetween the UE and BS.

FIG. 1 illustrates physical channels used in a 3GPP LTE system and asignal transmission method using the same.

When powered on or when a UE initially enters a cell, the UE performsinitial cell search involving synchronization with a BS in step S101.For initial cell search, the UE synchronizes with the BS and acquireinformation such as a cell Identifier (ID) by receiving a primarysynchronization channel (P-SCH) and a secondary synchronization channel(S-SCH) from the BS. Then the UE may receive broadcast information fromthe cell on a physical broadcast channel (PBCH). In the meantime, the UEmay check a downlink channel status by receiving a downlink referencesignal (DL RS) during initial cell search.

After initial cell search, the UE may acquire more specific systeminformation by receiving a physical downlink control channel (PDCCH) andreceiving a physical downlink shared channel (PDSCH) based oninformation of the PDCCH in step S102.

The UE may perform a random access procedure to access the BS in stepsS103 to S106. For random access, the UE may transmit a preamble to theBS on a physical random access channel (PRACH) (S103) and receive aresponse message for preamble on a PDCCH and a PDSCH corresponding tothe PDCCH (S104). In the case of contention-based random access, the UEmay perform a contention resolution procedure by further transmittingthe PRACH (S105) and receiving a PDCCH and a PDSCH corresponding to thePDCCH (S106).

After the foregoing procedure, the UE may receive a PDCCH/PDSCH (S107)and transmit a physical uplink shared channel (PUSCH)/physical uplinkcontrol channel (PUCCH) (S108), as a general downlink/uplink signaltransmission procedure. Here, control information transmitted from theUE to the BS is called uplink control information (UCI). The UCI mayinclude a hybrid automatic repeat and request (HARQ)acknowledgement(ACK)/negative-ACK (HARQ ACK/NACK) signal, a schedulingrequest (SR), channel state information (CSI), etc. The CSI includes achannel quality indicator (CQI), a precoding matrix index (PMI), a rankindicator (RI), etc. While the UCI is transmitted through a PUCCH ingeneral, it may be transmitted through a PUSCH when control informationand traffic data need to be simultaneously transmitted. The UCI may beaperiodically transmitted through a PUSCH at the request/instruction ofa network.

FIG. 2, including (a) and (b), illustrates a radio frame structure. In acellular OFDM wireless packet communication system, uplink/downlink datapacket transmission is performed on a subframe-by-subframe basis. Asubframe is defined as a predetermined time interval including aplurality of OFDM symbols. 3GPP LTE supports a type-1 radio framestructure applicable to FDD (Frequency Division Duplex) and a type-2radio frame structure applicable to TDD (Time Division Duplex).

FIG. 2(a) illustrates a type-1 radio frame structure. A downlinksubframe includes 10 subframes each of which includes 2 slots in thetime domain. A time for transmitting a subframe is defined as atransmission time interval (TTI). For example, each subframe has alength of lms and each slot has a length of 0.5 ms. A slot includes aplurality of OFDM symbols in the time domain and includes a plurality ofresource blocks (RBs) in the frequency domain. Since downlink uses OFDMin 3GPP LTE, an OFDM symbol represents a symbol period. The OFDM symbolmay be called an SC-FDMA symbol or symbol period. An RB as a resourceallocation unit may include a plurality of consecutive subcarriers inone slot.

The number of OFDM symbols included in one slot may depend on CyclicPrefix (CP) configuration. CPs include an extended CP and a normal CP.When an OFDM symbol is configured with the normal CP, for example, thenumber of OFDM symbols included in one slot may be 7. When an OFDMsymbol is configured with the extended CP, the length of one OFDM symbolincreases, and thus the number of OFDM symbols included in one slot issmaller than that in case of the normal CP. In case of the extended CP,the number of OFDM symbols allocated to one slot may be 6. When achannel state is unstable, such as a case in which a UE moves at a highspeed, the extended CP can be used to reduce inter-symbol interference.

When the normal CP is used, one subframe includes 14 OFDM symbols sinceone slot has 7 OFDM symbols. The first three OFDM symbols at most ineach subframe can be allocated to a PDCCH and the remaining OFDM symbolscan be allocated to a PDSCH.

FIG. 2(b) illustrates a type-2 radio frame structure. The type-2 radioframe includes 2 half frames. Each half frame includes 4(5) normalsubframes and 1(0) special subframe. Normal subframes are used for anuplink or a downlink according to UL-DL configuration. A subframeincludes 2 slots.

Table 1 shows subframe configurations in a radio frame according toUL-DL configuration.

TABLE 1 Downlink- to-Uplink Uplink- Switch- downlink point Subframenumber configuration periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U DS U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms  DS U U U D D D D D 4 10 ms  D S U U D D D D D D 5 10 ms  D S U D D D D DD D 6 5 ms D S U U U D S U U D

In Table 1, D denotes a downlink subframe, U denotes an uplink subframeand S denotes a special subframe. The special subframe includes DwPTS(Downlink Pilot TimeSlot), GP (Guard Period), and UpPTS (Uplink PilotTimeSlot). DwPTS is used for initial cell search, synchronization orchannel estimation in a UE. UpPTS is used for channel estimation in a BSand UL transmission synchronization acquisition in a UE. The GPeliminates UL interference caused by multi-path delay of a DL signalbetween a UL and a DL.

The radio frame structure is merely exemplary and the number ofsubframes included in the radio frame, the number of slots included in asubframe, and the number of symbols included in a slot can be vary.

FIG. 3 illustrates a resource grid of a downlink slot.

Referring to FIG. 3, a downlink slot includes a plurality of OFDMsymbols in the time domain. One downlink slot may include 7 OFDMsymbols, and one resource block (RB) may include 12 subcarriers in thefrequency domain. However, the present invention is not limited thereto.Each element on the resource grid is referred to as a resource element(RE). One RB includes 12×7(6) REs. The number N^(DL) of RBs included inthe downlink slot depends on a downlink transmit bandwidth. Thestructure of an uplink slot may be same as that of the downlink slot.

FIG. 4 illustrates a downlink subframe structure.

Referring to FIG. 4, a maximum of three (four) OFDM symbols located in afront portion of a first slot within a subframe correspond to a controlregion to which a control channel is allocated. The remaining OFDMsymbols correspond to a data region to which a physical downlink sharedchancel (PDSCH) is allocated. Examples of downlink control channels usedin LTE include a physical control format indicator channel (PCFICH), aphysical downlink control channel (PDCCH), a physical hybrid ARQindicator channel (PHICH), etc. The PCFICH is transmitted at a firstOFDM symbol of a subframe and carries information regarding the numberof OFDM symbols used for transmission of control channels within thesubframe. The PHICH is a response of uplink transmission and carries anHARQ acknowledgment (ACK)/negative-acknowledgment (NACK) signal. Controlinformation transmitted through the PDCCH is referred to as downlinkcontrol information (DCI). The DCI includes uplink or downlinkscheduling information or an uplink transmit power control command foran arbitrary UIE group.

Control information transmitted through a PDCCH is referred to as DCI.Formats 0, 3, 3A and 4 for uplink and formats 1, 1A, 1B, 1C, 1D, 2, 2A,2B and 2C for downlink are defined as DCI formats. Information fieldtypes, the number of information fields and the number of bits of eachinformation field depend on DCI format. For example, the DCI formatsselectively include information such as hopping flag, RB allocation, MCS(modulation coding scheme), RV (redundancy version), NDI (new dataindicator), TPC (transmit power control), HARQ process number, PMI(precoding matrix indicator) confirmation as necessary. A DCI format canbe used to transmit control information of two or more types. Forexample, DCI format 0/1A is used to carry DCI format 0 or DCI format 1,which are discriminated from each other by a flag field.

A PDCCH may carry a transport format and a resource allocation of adownlink shared channel (DL-SCH), resource allocation information of anuplink shared channel (UL-SCH), paging information on a paging channel(PCH), system information on the DL-SCH, information on resourceallocation of an upper-layer control message such as a random accessresponse transmitted on the PDSCH, a set of Tx power control commands onindividual UEs within an arbitrary UE group, a Tx power control command,information on activation of a voice over IP (VoIP), etc. A plurality ofPDCCHs can be transmitted within a control region. The UE can monitorthe plurality of PDCCHs. The PDCCH is transmitted on an aggregation ofone or several consecutive control channel elements (CCEs). The CCE is alogical allocation unit used to provide the PDCCH with a coding ratebased on a state of a radio channel. The CCE corresponds to a pluralityof resource element groups (REGs). A format of the PDCCH and the numberof bits of the available PDCCH are determined by the number of CCEs. TheBS determines a PDCCH format according to DCI to be transmitted to theUE, and attaches a cyclic redundancy check (CRC) to control information.The CRC is masked with a unique identifier (referred to as a radionetwork temporary identifier (RNTI)) according to an owner or usage ofthe PDCCH. If the PDCCH is for a specific UE, a unique identifier (e.g.,cell-RNTI (C-RNTI)) of the UE may be masked to the CRC. Alternatively,if the PDCCH is for a paging message, a paging identifier (e.g.,paging-RNTI (P-RNTI)) may be masked to the CRC. If the PDCCH is forsystem information (more specifically, a system information block(SIB)), a system information RNTI (SI-RNTI) may be masked to the CRC.When the PDCCH is for a random access response, a random access-RNTI(RA-RNTI) may be masked to the CRC.

FIG. 5 illustrates an uplink subframe structure used in LTE.

Referring to FIG. 5, a subframe 500 includes two 0.5 ms slots 501. Whena normal CP is used, each slot includes 7 symbols 502 each correspondingto an SC-FDMA symbol. A resource block 503 is a resource allocation unitcorresponding to 12 subcarriers in the frequency domain and to a slot inthe time domain. The uplink subframe is divided into a data region 504and a control region 505. The data region refers to a communicationresource used for a UE to transmit data such as audio data, packets,etc. and includes a PUSCH (physical uplink shared channel). The controlregion refers to a communication resource used for the UE to transmituplink control information (UCI) and includes a PUCCH (physical uplinkcontrol channel).

The PUCCH can be used to transmit the following control information.

-   -   SR (scheduling request): This is information used to request a        UL-SCH resource and is transmitted using On-Off Keying (OOK)        scheme.    -   HARQ ACK: This is a response to a downlink data packet (e.g.        codeword) on a PDSCH and indicates whether the downlink data        packet has been successfully received. A 1-bit ACK/NACK signal        is transmitted as a response to a single downlink codeword and a        2-bit ACK/NACK signal is transmitted as a response to two        downlink codewords. A HARQ-ACK response includes positive ACK        (simply, ACK), negative ACK (NACK), DTX or NACK/DTX. Here,        HARQ-ACK is used interchangeably with HARQ ACK/NACK and        ACK/NACK.    -   CSI (channel state information): This is feedback information        about a downlink channel. Feedback information regarding        multiple input multiple output (MIMO) includes rank indicator        (RI) and precoding matrix index (PMI). 20 bits are used for each        subframe.

The quantity of control information that a UE can transmit through asubframe depends on the number of SC-FDMA symbols available for controlinformation transmission. The SC-FDMA symbols available for controlinformation transmission correspond to SC-FDMA symbols other thanSC-FDMA symbols of the subframe, which are used for reference signaltransmission. In the case of a subframe in which a sounding referencesignal (SRS) is configured, the last SC-FDMA symbol of the subframe isexcluded from the SC-FDMA symbols available for control informationtransmission. A reference signal is used to detect coherence of thePUCCH. The PUCCH supports various formats according to informationtransmitted thereon.

Table 2 shows the mapping relationship between PUCCH formats and UCI inLTE(-A).

TABLE 2 PUCCH format UCI (Uplink Control Information) Format 1 SR(Scheduling Request) (non-modulated waveform Format 1a 1-bit HARQACK/NACK (SR exist/non-exist) Format 1b 2-bit HARQ ACK/NACK (SRexist/non-exist) Format 2 CQI (20 coded bits) Format 2 CQI and 1- or2-bit HARQ ACK/NACK (20 bits) (corresponding to only extended CP) Format2a CQI and 1-bit HARQ ACK/NACK (20 + 1 coded bits) Format 2b CQI and2-bit HARQ ACK/NACK (20 + 2 coded bits) Format 3 Up to 24-bit HARQACK/NACK + SR (LTE-A)

An SRS is transmitted through the last SC-FDMA symbol of the subframe(506). SRSs of multiple UEs, transmitted through the same SC-FDMAsymbol, can be discriminated according to frequency position/sequence.The SRS is transmitted aperiodically or periodically.

FIG. 6 illustrates a slot level structure of PUCCH formats 1a/1b. In thecase of PUCCH formats 1a/1b, the same control information is repeated ona slot basis in a subframe. UEs transmit ACK/NACK signals throughdifferent resources configured of different cyclic shifts (CSs)(frequency domain codes) of a CG-CAZAC (computer-generated constantamplitude zero auto correlation) sequence and orthogonal covers ororthogonal cover codes (OCs or OCCs) (time domain spreading codes). TheOC includes a Walsh/DFT orthogonal code, for example. When the number ofCSs is 6 and the number of OCs is 3, 18 UEs can be multiplexed in thesame PRB (physical resource block) on the basis of a single antenna.

FIG. 7 illustrates a slot level structure of PUCCH formats 2/2a/2b. Asubframe includes 10 QPSK data symbols in addition to a reference signal(RS). Each QPSK symbol is spread according to CS in the frequency domainand then mapped to a corresponding SC-FDMA symbol. The RS can bemultiplexed according to CDM using a CS. For example, if the number ofavailable CSs is 12 or 6, 12 or 6 UEs can be multiplexed in the samePRB.

FIG. 8 illustrates a carrier aggregation (CA) communication system. Tosupport a wider uplink/downlink bandwidth, multiple UL/DL componentcarriers are aggregated. CCs may be contiguous or non-contiguous in thefrequency domain. The bandwidth of each component carrier can beindependently determined. Asymmetrical carrier aggregation in which thenumber of UL CCs is different from the number of DL CCs is possible.Control information may be transmitted and received through a specificCC only. The specific CC may be referred to as a primary CC and otherCCs may be referred to as secondary CCs. For example, cross-carrierscheduling (or cross-CC scheduling) is applied, a PDCCH for downlinkallocation can be transmitted through DL CC#0 and a PDSCH correspondingto the PDCCH can be transmitted through DL CC#2. The term “componentcarrier” can be replaced by equivalent terms (e.g. carrier, cell, etc.).

For cross-CC scheduling, a carrier indicator field (CIF) is used.Setting of presence or absence of a CIF in a PDCCH can be enabledthrough higher layer signaling (e.g. RRC signaling) semi-staticallyUE-specifically (or UE-group-specifically). PDCCH transmission can bearranged as follows.

CIF disabled: a PDCCH on a DL CC is used to allocate a PDSCH resource onthe same DL CC or a PUSCH resource on a linked UL CC.

No CIF

-   -   CIF enabled: a PDCCH on a DL CC can be used to allocate a PDSCH        or PUSCH resource on a specific DL/UL CC from among a plurality        of aggregated DL/UL CCs using the CIF.

LTE DCI format extended to have the CIF.

CIF is a fixed x-bit field (e.g. x=3) (when the CIF is set).

CIF position is fixed irrespective of DCI format size (when the CIF isset).

When the CIF is present, a BS can allocate a monitoring DL CC (set) inorder to reduce BD complexity in a UE. For PDSCH/PUSCH scheduling, theUE can detect/decode a PDCCH only in the corresponding DL CC. The BS cantransmit the PDCCH through the monitoring DL CC (set) only. Themonitoring DL CC set can be set UE-group-specifically orcell-specifically.

FIG. 9 illustrates a case in which 3 DL CCs are aggregated and DL CC Ais set as a monitoring DL CC. When the CIF is disabled, each DL CC cantransmit a PDCCH that schedules a PDSCH of each DL CC without the CIFaccording to LTE PDCCH rules. When the CIF is enabled through higherlayer signaling, only DL CC A can transmit PDCCHs that schedule PDSCHsof other DL CCs as well as the PDSCH thereof using the CIF. A PDCCH isnot transmitted through DL CC B and DL CC C which are not set as amonitoring DL CC. Here, “monitoring DL CC (MCC)” can be replaced byequivalent terms such as a monitoring carrier, monitoring cell,scheduling carrier, scheduling cell, serving carrier, serving cell, etc.A PCC can be referred to as an MCC for scheduling. A DL CC through whicha PDSCH corresponding to a PDCCH is transmitted and a UL CC throughwhich a PUSCH corresponding to the PUCCH is transmitted can be referredto as scheduled carriers, scheduled cells, etc.

A beyond LTE-A system based on TDD may consider aggregation of aplurality of CCs in different UL-DL configurations. In this case,different A/N timings (i.e. UL SF timing at which A/N with respect to DLdata transmitted through each DL SF is transmitted) may be set for a PCCand an SCC according to UL-DL configurations of the corresponding CCs.For example, UL SF timing at which A/N is transmitted for the same DL SFtiming (DL data transmitted at the DL SF timing) can be set differentlyfor the PCC and SCC, and a DL SF group for which A/N feedback istransmitted at the same UL SF timing can be set differently for the PCCand the SCC. Furthermore, link directions (i.e. DL or UL) of the PCC andthe SCC may be set differently in the same SF timing. For example, theSCC can be set as UL SF at a specific SF timing, whereas the PCC can beset as DL SF at the specific SF timing.

In addition, the beyond LTE-A system based on TDD may support cross-CCscheduling in a CA situation based on different TDD UL-DL configurations(referred to as different TDD CA for convenience). In this case,different UL grant timings (DL SF timing at which a UL grant thatschedules UL transmission is transmitted) and different PHICH timings(DL SF timing at which a PHICH corresponding to UL data is transmitted)may be set for an MCC (monitoring CC) and an SCC. For example, a DL SFin which a UL grant/PHICH is transmitted can be set differently for thesame UL SF. Furthermore, a UL SF group for which a UL grant or PHICHfeedback is transmitted in the same DL SF can be set differently for theMCC and the SCC. In this case, link directions of the MCC and the SCCmay be set differently for the same SF timing. For example, specific SFtiming can be set to a DL SF in which a UL grant/PHICH will betransmitted in case of the SCC, whereas the specific SF timing can beset to a UL SF in case of the MCC.

When SF timing (referred to as collided SF hereinafter) at which linkdirections of the PCC and SCC are different from each other due todifferent TDD CA configurations is present, only a CC of the PCC andSCC, which has a specific link direction or has the same link directionas that of a specific CC (e.g. PCC), can be handled as operable at theSF timing due to hardware configuration of the UE or for otherreasons/purposes. This scheme is called HD (Half-Duplex)-TDD CA forconvenience. For example, when SF collision occurs because specific SFtiming is set to a DL SF in case of PCC and the SF timing is set to a ULSF in case of SCC, only a PCC (i.e. DL SF set to the PCC) correspondingto DL at the SF timing is handled as operable and an SCC (i.e. UL SF setto the SCC) corresponding to UL is not handled as operable at the SFtiming (and vice versa).

FIG. 10 illustrates a HD-TDD CA structure. In the figure, shaded parts Xshow a CC (link direction) that are restricted from being used in acollided SF. Referring to FIG. 10, when a PCC is set to a UL SF and anSCC is set to a DL SF, only the UL SF of the PCC may be handled asoperable and the DL SF of the SCC may not be handled as operable. In thesame situation, only the DL SF of the SCC may be handled as operable andthe UL SF of the PCC may not be handled as operable.

A description will be given of a subframe operation method forsupporting HD operation efficiently and stably when plural CCs indifferent TDD UL-DL configurations are aggregated. Specifically, amethod of reconfiguring an SF type for stable HD operation when only aspecific (DL or UL) direction is handled as operable for each collidedSF combination, in consideration of all possible collided SFcombinations between an XCC (PCC or SCC) and a YCC (SCC or PCC), isproposed. In addition, an efficient link direction configuration schemefor each collided SF combination is proposed to minimize resource loss(caused by collided SFs) in terms of SF usage.

In the specification, (X1, X2: Y1, Y2) represents that the directions ofthe first and second SFs (in a time order) of the XCC respectivelycorrespond to X1 and X2 and the directions of the first and second SFsof the YCC respectively correspond to Y1 and Y2. In addition, D, U and Srespectively denote a DL SF, a UL SF and a special SF, and X denotes aCC (link direction) that is not used (in a collided SF). In addition,for any reason, only the SCC may be set to X (i.e. the PCC may not beset to X).

A detailed description will be given of collided SF combinations.

-   -   Case #1: (X1, X2:Y1, Y2)=(U, D:U, U)        -   SF recfg 1-1: (U, D:U, U) is set to (U, D:U, X).

When the second SF direction of the XCC is set to D, atransmission/reception timing gap is present between U and D of the XCCand thus the entire transmission period can be secured in the first U ofthe YCC. That is, when a UL transmission timing synchronization (e.g.timing advance) difference between the XCC and YCC is insignificant,transmission end timing in the first U of the YCC is present within thetransmission/reception timing gap of the XCC (i.e. present sufficientlyprior to reception start timing in D of the XCC). Accordingly, linkdirection setting of this scheme is useful in terms of resourceutilization efficiency.

-   -   SF recfg 1-2: (U, D:U, U) is set to (U, X:U, U).

When the second SF direction of the YCC is set to U, the entiretransmission period can be secured in the first U of the XCC because twoSFs of the YCC are contiguous Us. That is, the entire transmissionperiod can be maintained without loss in the first U of the XCC sinceonly transmission operation through U is continuously performed withouttransmission/reception switching in the YCC. Accordingly, link directionsetting of the present scheme is useful in terms of resource utilizationefficiency.

According to SF recfg 1-1, the transmission end timing in the first U ofthe YCC may not be present sufficiently prior to the reception starttiming in the D of the XCC due to a significant UL transmission timingsynchronization difference between the XCC and the YCC. In this case,the transmission end timing in the first U of the YCC may need to beadjusted such that transmission/reception switching time between U and Dof the XCC is secured (i.e. the transmission end timing in the first Uof the YCC becomes similar or corresponds (in the worst case) to thetransmission end timing in U of the XCC). This reduces an SF period inwhich transmission can be performed through the first U of the YCC andthus resource utilization efficiency may decrease.

Therefore, when a link direction is configured according to SF recfg1-1, the following SF type reconfiguration scheme can be considered forY1=U of the YCC.

-   -   Sol 1: A BS can signal, to a UE, an SF period with respect to U,        the number of symbols (constituting an SF), the last symbol        index (in the SF) or information through which the same can be        inferred. The UE can signal, to the BS, an SF period in which        transmission can be performed for Y1=U of the YCC, the number of        symbols (constituting an SF), the last symbol index (in the SF)        or information through which the same can be inferred. Here, a        UL symbol includes an SC-FDMA symbol. Accordingly, the UE can        perform UL transmission only in an available SF period and then        carry out transmission/reception switching operation at an        appropriate time. When YCC=PCC, a shortened PUCCH format may be        used for transmission of UCI such as ACK/NACK, CSI, etc. through        Y1=U. Here, the shortened PUCCH format refers to a PUCCH format        in which UL signal transmission is performed using only symbols        other than symbols available for SRS transmission in an SF. In        the meantime, transmission of a UL signal/channel (e.g. a PUCCH,        random access preamble, SRS), which is configured/ordered to        include all or some remaining symbol(s) except for an available        SF period in an SF, can be dropped/abandoned. When a PUSCH is        transmitted through Y1=U of the YCC, the PUSCH can be        rate-matched or punctured in consideration of the available SF        period (and/or symbol(s) other than the available SF period).    -   Sol 2: Only U and D of the XCC can be operated by limiting use        of Y1=U of the YCC (i.e. (U, D:U, U) is set to (U, D:X, X)).        Equivalently, the UE can operate on the assumption that a PUSCH        transmission in Y1=U of the YCC is not scheduled. That is, the        UE may not transmit the PUSCH in Y1=U of the YCC irrespective of        whether the PUSCH transmission in Y1=U of the YCC has been        scheduled or not. Accordingly, the UE can omit/drop/abandon        PUSCH transmission in Y1=U of the YCC even though PUSCH        transmission is scheduled. Furthermore, the UE can        omit/drop/abandon transmission of a PUCCH/PRACH/SRS configured        to be transmitted in Y1=U of the YCC.    -   Sol 3: Use of last M (SC-FDMA) symbols of Y1=U of the YCC can be        additionally limited. M is an integer equal to or greater than        1, for example, 1. Transmission of a UL signal/channel (e.g.        periodic SRS, aperiodic SRS, PUCCH (format 2/2a/2b) carrying        periodic CSI, random access preamble), which is        configured/ordered to be include all or some of the M symbol(s),        can be dropped/abandoned. When a PUSCH is transmitted in Y1=U of        the YCC, the PUSCH can be rate-matched or punctured in        consideration of the M symbols. When a PUCCH (e.g. PUCCH        carrying ACK/NACK) is transmitted in Y1=U of the YCC, the PUCCH        can be configured to use a shortened PUCCH format in which a        signal is transmitted using symbols other than the M symbols.        The UE can be configured to omit/drop/abandon transmission of a        PUCCH/PRACH/SRS configured to be transmitted in Y1=U of the YCC.    -   Sol 4: When a PUSCH is transmitted in Y1=U of the YCC, the UE        can apply rate matching or puncturing to some last (e.g. M)        symbols constituting the PUSCH. In addition, the UE can        omit/drop/abandon transmission of a PUCCH/PRACH/SRS configured        to be transmitted in Y1=U of the YCC.

Case #2: (X1, X2: Y1, Y2)=(D, D:S, U)

-   -   SF recfg 2-1: (D, D:S, U) is set to (D, D:S, X).

When the second SF direction of the XCC is set to D, the entirereception period (i.e. the entire DwPTS period) can be secured in Y1=Sof the YCC since two SFs of the XCC are contiguous Ds. That is, theentire reception period can be maintained without loss in Y1=S of theYCC since only reception operation through D is continuously performedwithout transmission/reception switching in the XCC. Accordingly, linkdirection setting of the present scheme is useful in terms of resourceutilization efficiency. UL transmission in an UpPTS period set in Y1=Sof the YCC can be dropped. For example, transmission of a ULsignal/channel (e.g. periodic SRS, aperiodic SRS, random accesspreamble), configured/ordered to be transmitted in Y1=S (i.e. UpPTSperiod) of the YCC, can be dropped/abandoned.

-   -   SF recfg 2-2: (D, D:S, U) is set to (D, X:S, U).

When the second SF direction of the YCC is set to U, the entirereception period cannot be secured in X1=D of the XCC because atransmission/reception switching gap is present between S and U of theYCC. That is, reception end timing in X1=D of the XCC may need to beadjusted such that transmission/reception switching time of the YCC issecured for HD operation even if DL reception timing of the XCC issynchronized with DL reception timing of the YCC. That is, the receptionend timing in X1=D of the XCC may need to be controlled to be similar toor to correspond to (in the worst case) reception end timing in Y1=S ofthe YCC. This may reduce an SF period in which reception can beperformed through X1=D of the XCC, and thus resource utilizationefficiency may decrease.

When a link direction setting scheme such as SF recfg 2-2 is applied,the following SF type resetting scheme may be applied to X1=D of theXCC. This scheme can be applied when a UL signal/channel is transmittedthrough UpPTS of Y1=S and/or a UL signal/channel is transmitted throughY2=U.

-   -   Alt 1: The BS can signal, to the UE, an SF period with respect        to X1=D of the XCC, the number of symbols (constituting an SF),        the last symbol index (in the SF) or information through which        the same can be inferred. The UE can signal, to the BS, an SF        period in which reception can be performed for X1=D of the XCC,        the number of symbols (constituting an SF), the last symbol        index (in the SF) or information through which the same can be        inferred. Here, a DL symbol includes an OFDM symbol.        Accordingly, the UE can perform DL reception only in an        available SF period and then carry out transmission/reception        switching operation at an appropriate time.    -   Alt 2: The same SF structure as S (i.e. S configured based on a        special SF configuration which is set for the YCC) configured in        the YCC can be applied to X1=D of the XCC. For example, only        part corresponding to DL in S of the YCC can be applied to X1=D        of the XCC.    -   Alt 3: The same SF structure as S (i.e. S configured based on a        special SF configuration which is set for the XCC) configured in        the XCC can be applied to X1=D of the XCC. For example, only        part corresponding to DL in S of the XCC can be applied to X1=D        of the XCC.    -   Alt 4: S corresponding to a smallest DL region between S        configured in the XCC and S configured in the YCC can be applied        to X1=D of the XCC. For example, only part corresponding to DL        in the corresponding S can be applied to X1=D of the XCC.    -   Alt 5: A special SF configuration to be applied to X1=D of the        XCC is additionally signaled and an S structure based on the        special SF configuration is applicable to X1=D of the XCC. For        example, only part corresponding to DL in the corresponding S        can be applied to X1=D of the XCC.    -   Alt 6: Use of X1=D of the XCC can be additionally limited (i.e.        (D, D:S, U) is set to (X, X:S, U) such that only S and U of the        YCC are operated). Equivalently, the UE can operate on the        assumption that a PCFICH/PHICH/PDCCH and a PDSCH transmission in        X1=D of the XCC are not scheduled. That is, the UE can        omit/drop/abandon a process for receiving scheduling information        regarding the PCFICH/PHICH/PDCCH and PDSCH in X1=D of the XCC        irrespective of whether the BS has transmitted the signals or        not.    -   Alt 7: An S structure corresponding to a smallest DL region        (i.e. DwPTS period) can be applied to X1=D of the XCC. For        example, only part corresponding to DL in the corresponding S        can be applied to X1=D of the XCC. Otherwise, the UE can operate        on the assumption that a PDSCH (e.g. DL grant PDCCH) is not        scheduled in X1=D of the XCC. That is, the UE can        omit/drop/abandon a process for receiving a DL grant PDCCH        signal and a PDSCH signal corresponding thereto in X1=D of the        XCC irrespective of whether the BS has actually transmitted the        signals or not.    -   Alt 8: When a PDSCH is transmitted/received through X1=D of the        XCC, the UE can omit an operation of detecting/receiving some        (e.g. K) last DL symbols constituting the PDSCH. Here, a DL        symbol includes an OFDM symbol.

When Alts 1 to 8 are applied, use of a UpPTS period (i.e. SC-FDMAsymbols corresponding thereto) set in Y1=S of the YCC can beadditionally limited to sufficiently secure a DL reception period inX1=D of the XCC. Here, UL transmission through the UpPTS period (i.e.transmission of a UL signal/channel (e.g. periodic SRS, aperiodic SRS,random access preamble) configured/ordered to be transmitted through theUpPTS period) in Y1=S of the YCC can be omitted/dropped. In the case ofAlts 2, 3 and 4, a period corresponding to the sum of the DwPTS periodconfigured in the YCC or XCC and the UpPTS period configured in the YCCor the sum of the smallest DwPTS period between the DwPTS periodsconfigured in the YCC/XCC and the UpPTS period configured in the YCC canbe determined as the entire DL reception period in X1=D of the XCC.Here, UL transmission in the UpPTS period in Y1=S of the YCC can be setthrough RRC signaling.

Alternatively, when the link direction setting scheme such as SF recfg2-2 is applied, the following SF type resetting scheme for Y2=U of theYCC is proposed to maintain the entire DL reception period of X1=D ofthe XCC without loss. Here, for Y1=S of the YCC, only the DwPTS periodconfigured in the corresponding S is applied (i.e. DL receptionoperation in the corresponding period is performed) and use of the UpPTSperiod configured in the corresponding S (UL transmission operation inthe corresponding period) can be omitted. This is applicable to a casein which a DL signal/channel is transmitted through X1=D of the XCC.

-   -   Alt 9: The BS can signal, to the UE, an SF period with respect        to Y2=U of the YCC, the number of symbols (constituting an SF),        the first symbol index (in the SF) or information through which        the same can be inferred. The UE can signal, to the BS, an SF        period in which transmission can be performed for Y2=U of the        YCC, the number of symbols (constituting an SF), the first        symbol index (in the SF) or information through which the same        can be inferred. Here, a UL symbol includes an SC-FDMA symbol.        Accordingly, the UE can perform UL transmission only in an        available SF period. In the meantime, transmission of a UL        signal/channel (e.g. a PUCCH, random access preamble, SRS),        which is configured/instructed to include all or some remaining        symbol(s) except for an available SF period in an SF and to be        transmitted, can be dropped/abandoned. When a PUSCH is        transmitted through Y2=U of the YCC, the PUSCH can be        rate-matched or punctured in consideration of the available SF        period (and/or symbols other than the available SF period).    -   Alt 10: Only D of the XCC and S of the YCC can be operated by        additionally limiting use of Y2=U of the YCC (i.e. (D, D:S, U)        is set to (D, X:S, X)). Equivalently, the UE can operate on the        assumption that a PUSCH transmission in Y2=U of the YCC is not        scheduled. That is, the UE may not transmit the PUSCH in Y2=U of        the YCC irrespective of whether the PUSCH transmission in Y2=U        of the YCC has been scheduled or not. Accordingly, the UE can        omit/drop/abandon PUSCH transmission in Y2=U of the YCC even        though PUSCH transmission is scheduled. Furthermore, the UE can        omit/drop/abandon transmission of a PUCCH/PRACH configured to be        transmitted through Y2=U of the YCC.    -   Alt 11: Use of first L (SC-FDMA) symbols of Y2=U of the YCC can        be additionally limited. Transmission of a UL signal/channel        (e.g. PUCCH, random access preamble), which is        configured/ordered to be transmitted including all or some of        the L symbols, can be dropped/abandoned. When a PUSCH is        transmitted in Y2=U of the YCC, the PUSCH can be rate-matched or        punctured in consideration of the L symbols. The UE can        omit/drop/abandon transmission of a PUCCH/PRACH configured to be        transmitted in Y2=U of the YCC.    -   Alt 12: When a PUSCH is transmitted in Y2=U of the YCC, the UE        can apply rate matching or puncturing to some (e.g. L) first        symbols constituting the PUSCH. In addition, the UE can        omit/drop/abandon transmission of a PUCCH/PRACH configured to be        transmitted in Y2=U of the YCC.

As alternative scheme for configuring a link direction, such as SF recfg2-1, the methods of Alts 1 to 8 may be applicable in order to support aUpPTS period (i.e. UL transmission in the corresponding period) which isconfigured in Y1=S of the YCC.

Considering SF resource utilization efficiency, SF recfg 1-1 or SF recfg1-2 is applicable to Case #1 and only SF recfg 2-1 may be applicable toCase #2. In addition, only SF recfg 1-2 may be applicable to Case #1 andonly SF recfg 2-1 may be applicable to Case #2 even in consideration ofa UL transmission timing synchronization difference between CCs.

Based on the above-described proposed schemes, a scheme of configuringlink direction when two or more continuous SFs form a collided SF isdescribed.

In the following description, (X1, X2, X3: Y1, Y2, Y3) represents thatfirst, second and third SF directions (in a time order) of the XCCrespectively correspond to X1, X2 and X3 and first, second and third SFdirections of the YCC respectively correspond to Y1, Y2 and Y3.Similarly, (X1, X2, X3, X4:Y1, Y2, Y3, Y4) represents that first,second, third and fourth SF directions (in chronological order) of theXCC respectively correspond to X1, X2, X3 and X4 and first, second,third and fourth SF directions of the YCC respectively correspond to Y1,Y2, Y3 and Y4.

Case #3: (X1, X2, X3:Y1, Y2, Y3) =(U, D, D:U, U, U)

-   -   SF recfg 3-1: (U, D, D:U, U, U) is set to (U, D, D:U, X, X).

This scheme is identical/similar to SF recfg 1-1. Sols 1 to 4 areapplicable to Y1=U.

-   -   SF recfg 3-2: (U, D, D:U, U, U) is set to (U, X, X:U, U, U).

This scheme is identical/similar to SF recfg 1-2.

-   -   SF recfg 3-3: (U, D, D:U, U, U) is set to (U, D, X:U, X, U).

It is necessary to secure a transmission/reception switching gap betweenX2=D and Y3=U for HD operation. To achieve this, Alts 1 to 12 areapplicable to X2=D (or Y3=U). In addition, Sols 1 to 4 are applicable toY1=U.

-   -   SF recfg 3-4: (U, D, D:U, U, U) is set to (U, X, D:U, U, X).

A transmission/reception timing gap may be present between Y2=U andX3=D. In addition, Sols 1 to 4 are applicable to Y2=U.

Case #4: (X1, X2, X3:Y1, Y2, Y3)=(D, D, D:S, U, U)

-   -   SF recfg 4-1: (D, D, D:S, U, U) is set to (D, D, D:S, X, X).

This scheme is identical/similar to SF recfg 2-1. Alts 1 to 8 areapplicable to X1=D.

-   -   SF recfg 4-2: (D, D, D:S, U, U) is set to (D, X, X:S, U, U).

This scheme is identical/similar to SF recfg 2-2. Alts 1 to 12 areapplicable to X1=D (or Y2=D).

-   -   SF recfg 4-3: (D, D, D:S, U, U) is set to (D, D, X:S, X, U).

It is necessary to secure a transmission/reception switching gap betweenX2=D and Y3=U for HD operation. To achieve this, Alts 1 to 12 areapplicable to X2=D (or Y3=U).

-   -   SF recfg 4-4: (D, D, D:S, U, U) is set to (D, X, D:S, U, X).

Since a transmission/reception timing gap is present between Y2=U andX3=D, there is no SF resource loss with respect to Y2 and X3. Alts 1 to12 can be applied to X1=D (or Y2=U) in order to secure atransmission/reception switching gap between X1=D and Y2=U. In addition,Sols 1 to 4 are applicable to Y2=U.

Case #5: (X1, X2, X3, X4:Y1, Y2, Y3, Y4) =(D, D, D, D:S, U, U, D)

-   -   SF recfg 5-1: (D, D, D, D:S, U, U, U) is set to (D, D, D, D:S,        X, X, X).

This scheme is identical/similar to SF recfg 2-1. Alts 1 to 8 areapplicable to X1=D.

-   -   SF recfg 5-2: (D, D, D, D:S, U, U, U) is set to (D, X, X, X:S,        U, U, U).

This scheme is identical/similar to SF recfg 2-2. Alts 1 to 12 areapplicable to X1=D (or Y2=D).

-   -   SF recfg 5-3: (D, D, D, D:S, U, U, U) is set to (D, D, D, X:S,        X, X, U).

It is necessary to secure a transmission/reception switching gap betweenX3=D and Y4=U for HD operation. To achieve this, Alts 1 to 12 areapplicable to X3=D (or Y4=U).

-   -   SF recfg 5-4: (D, D, D, D:S, U, U, U) is set to (D, X, D, D:S,        U, X, X).

To secure a transmission/reception switching gap between X1=D and Y2=U,Alts 1 to 12 are applicable to X1=D (or Y2=U). Furthermore, Sols 1 to 4are applicable to Y2=U.

-   -   SF recfg 5-5: (D, D, D, D:S, U, U, U) is set to (D, D, X, D:S,        X, U, X).

It is necessary to secure a transmission/reception switching gap betweenX2=D and Y3=U for HD operation. To achieve this, Alts 1 to 12 areapplicable to X2=D (or Y3=U). In addition, Sols 1 to 4 are applicable toY3=U.

-   -   SF recfg 5-6: (D, D, D, D:S, U, U, U) is set to (D, X, X, D:S,        U, U, X).

To secure a transmission/reception switching gap between X1=D and Y2=U,Alts 1 to 12 are applicable to X1=D (or Y2=U). Furthermore, Sols 1 to 4are applicable to Y3=U.

-   -   SF recfg 5-7: (D, D, D, D:S, U, U, U) is set to (D, D, X, X:S,        X, U, U).

It is necessary to secure a transmission/reception switching gap betweenX2=D and Y3=U for HD operation. To achieve this, Alts 1 to 12 areapplicable to X2=D (or Y3=U).

-   -   SF recfg 5-8: (D, D, D, D:S, U, U, U) is set to (D, X, D, X:S,        U, X, U).

It is necessary to secure a transmission/reception switching gap betweenX1=D and Y2=U and between X3=D and Y4=U for HD operation. To achievethis, Alts 1 to 12 are applicable to X1=D (or Y2=U) and X3=D (or Y4=U).

Considering SF resource utilization efficiency, SF recfg 3-1, SF recfg3-2 or SF recfg 3-4 may be applicable to Case #3, only SF recfg 4-1 maybe applicable to Case #4 and only SF recfg 5-1 may be applicable to Case#5. In addition, only SF recfg 3-2 may be applicable to Case #3, only SFrecfg 4-1 may be applicable to Case #4 and only SF recfg 5-1 may beapplicable to Case #5 even in consideration of a UL transmission timingsynchronization difference between CCs. Furthermore, it is possible toexclude only SF recfg 5-8 which is expected to require a largest SFresource loss for securing a transmission/reception switching gap fromamong the above-described schemes.

FIGS. 11 and 12 illustrate SF reconfiguration methods according toembodiments of the present invention. The SF reconfiguration methodscorrespond to generalization of Sols 1 to 4 and Alts 1 to 12. In FIGS.11 and 12, (X(k), X(k+1):Y(k), Y(k+1)) represents that a k-th and(k+1)-th SF directions (in a time order) of the XCC respectivelycorrespond to X(k) and X(k+1) and a k-th and (k+1)-th SF directions ofthe YCC respectively correspond to Y(k) and Y(k+1).

Referring to FIG. 11, SF reconfiguration is performed as follows when acollided SF occurs. FIG. 11 shows a state after the collided SF has beenreconfigured.

(X(k), X(k+1):Y(k), Y(k+1)) (U, D:U, X) or (X, D:U, X)

-   -   Sols 1 to 4 may be applicable to Y(k)=U. UCI including ACK/NACK        and CSI is transmitted on a PCC, and thus a SF recfg (Sols 1 to        4 may need to be applied) may be permitted only for YCC=SCC and        not permitted for YCC=PCC.

Referring to FIG. 12, SF reconfiguration is performed as follows when acollided SF is generated. FIG. 12 shows a state after the collided SFhas been reconfigured.

(X(k), X(k+1):Y(k), Y(k+1))=>(D, X:S, U) or (D, X:X, U)

-   -   Alts 1 to 12 may be applicable to X(k)=D (or Y(k+1)=U). System        information, RRC/NAC signal and synchronization signal are        transmitted on the PCC, and thus an SF recfg (Alts 1 to 12 need        to be applied) may be permitted only for XCC=SCC and not        permitted for XCC=PCC.

In addition, when SF recfg 2-1 (i.e. X1, X2:Y1, Y2)=>(D, D:S, X)) isapplied to Case #2, use of the entire period of Y1=S (including bothDwPTS and UpPTS) can be additionally limited in order to support a DL SFperiod of the XCC without loss. That is, only two Ds of the XCC can beoperated for two corresponding SFs by setting (X1, X2:Y1, Y2) to (D,D:X, X). Otherwise, the UE can operate on the assumption that aPCFICH/PHICH/PDCCH and a PDSCH transmission in Y1=S (as well as a ULsignal/channel transmitted through UpPTS) are not scheduled.

In the following cases, situations/operations similar to Case #1 andCase #2 may occur. In this case, Sols 1 to 4 and Alts 1 to 12 may beapplicable according to conditions.

Case #A: (X1, X2:Y1, Y2)=(D, S:D, D) or (D, X:D, D)

-   -   The relationship between X2=S and Y2=D may be similar to the        relationship between X1=D and Y1=S of Case #2 (which can be set        to (D, X:D, D). Accordingly, an SF reconfiguration method        according to SF recfg 2-1 and SF recfg 2-2 is applicable. For        example, Alts 1 to 8 or modified/extended methods thereof are        applicable to Y2=D according to whether use of the entire period        of X2=S or an UpPTS period in the corresponding S is limited or        not.

Case #B: (X1, X2:Y1, Y2)=(U, D:D, D), (U, D:X, D) or (X, D:D, D)

-   -   The relationship between X1=U and Y2=D may be similar to the        relationship between X2=D and Y1=U of Case #1 (which can be set        to (U, D:X, D) or (X, D:D, D). Accordingly, an SF        reconfiguration method related to SF recfg 1-1 is applicable (to        a case in which (X1, X2:Y1, Y2) is set to (U, D:X, D)). For        example, Sols 1 to 4 may be applicable to X1=U.

Furthermore, it is possible to configure a scheme for the UE as one ofSols 1 to 4 and/or Alts 1 to 12 through a higher layer signaling (e.g.RRC signaling).

FIG. 13 illustrates a BS, a relay and a UE applicable to the presentinvention.

Referring to FIG. 13, a wireless communication system includes a BS 110and a UE 120. When the wireless communication system includes a relay,the BS or UE can be replaced by the relay.

The BS includes a processor 112, a memory 114, an RF unit 116. Theprocessor 112 may be configured to implement the procedures and/ormethods proposed by the present invention. The memory 114 is connectedto the processor 112 and stores information related to operations of theprocessor 112. The RF unit 116 is connected to the processor 112,transmits and/or receives an RF signal. The UE 120 includes a processor122, a memory 124, and an RF unit 126. The processor 112 may beconfigured to implement the procedures and/or methods proposed by thepresent invention. The memory 124 is connected to the processor 122 andstores information related to operations of the processor 122. The RFunit 126 is connected to the processor 122, transmits and/or receives anRF signal.

The embodiments of the present invention described hereinbelow arecombinations of elements and features of the present invention. Theelements or features may be considered selective unless otherwisementioned. Each element or feature may be practiced without beingcombined with other elements or features. Further, an embodiment of thepresent invention may be constructed by combining parts of the elementsand/or features. Operation orders described in embodiments of thepresent invention may be rearranged. Some constructions of any oneembodiment may be included in another embodiment and may be replacedwith corresponding constructions of another embodiment. It will beobvious to those skilled in the art that claims that are not explicitlycited in each other in the appended claims may be presented incombination as an embodiment of the present invention or included as anew claim by a subsequent amendment after the application is filed.

In the embodiments of the present invention, a description is madecentering on a data transmission and reception relationship among a BS,a relay, and an MS. In some cases, a specific operation described asperformed by the BS may be performed by an upper node of the BS. Namely,it is apparent that, in a network comprised of a plurality of networknodes including a BS, various operations performed for communicationwith an MS may be performed by the BS, or network nodes other than theBS. The term ‘BS’ may be replaced with the term ‘fixed station’, ‘NodeB’, ‘enhanced Node B (eNode B or eNB)’, ‘access point’, etc. The term‘UE’ may be replaced with the term ‘Mobile Station (MS)’, ‘MobileSubscriber Station (MSS)’, ‘mobile terminal’, etc.

The embodiments of the present invention may be achieved by variousmeans, for example, hardware, firmware, software, or a combinationthereof. In a hardware configuration, the methods according to theembodiments of the present invention may be achieved by one or moreApplication Specific Integrated Circuits (ASICs), Digital SignalProcessors (DSPs), Digital Signal Processing Devices (DSPDs),Programmable Logic Devices (PLDs), Field Programmable Gate Arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

In a firmware or software configuration, the embodiments of the presentinvention may be implemented in the form of a module, a procedure, afunction, etc. For example, software code may be stored in a memory unitand executed by a processor. The memory unit is located at the interioror exterior of the processor and may transmit and receive data to andfrom the processor via various known means.

Those skilled in the art will appreciate that the present invention maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent invention. The above embodiments are therefore to be construedin all aspects as illustrative and not restrictive. The scope of theinvention should be determined by the appended claims and their legalequivalents, not by the above description, and all changes coming withinthe meaning and equivalency range of the appended claims are intended tobe embraced therein.

The present invention is applicable to a UE, BS or other devices of awireless mobile communication system. Specifically, the presentinvention is applicable to a method for transmitting uplink controlinformation and an apparatus for the same.

The invention claimed is:
 1. A method of performing communications by auser equipment (UE) in a time division duplexing (TDD)-based wirelesscommunication system, the method comprising: configuring a primarycomponent carrier (PCC) and a secondary component carrier (SCC), whereinthe PCC and the SCC have different uplink-downlink (UL-DL)configurations; and for a subframe #k, where the PCC is a specialsubframe including a downlink pilot time slot (DwPTS), a guard period(GP) and an uplink pilot time slot (UpPTS), and the SCC is a downlinksubframe, performing UE operations under an assumption that a physicaldownlink shared channel (PDSCH) is not received through any part of thesubframe #k of the SCC regardless of a length of the DwPTS of thesubframe #k of the PCC.
 2. The method according to claim 1, whereinsubframe patterns of the PCC and the SCC are given according to UL-DLconfigurations as follows: Subframe number UL-DL configuration 0 1 2 3 45 6 7 8 9 0 D S U U U D S U U U 1 D S U U D D S U U D 2 D S U D D D S UD D 3 D S U U U D D D D D 4 D S U U D D D D D D 5 D S U D D D D D D D 6D S U U U D S U U D where D denotes a downlink subframe, U denotes anuplink subframe and S denotes a special subframe.


3. The method according to claim 1, wherein the DwPTS of the subframe #kof the PCC overlaps with a data region of the subframe #k of the SCC,the data region being a time domain region reserved for PDSCHassignment.
 4. The method according to claim 1, wherein the UEoperations are performed under an assumption that the PDSCH is notreceived through any part of the subframe #k of the SCC regardless ofwhether the DwPTS of the subframe #k of the PCC overlaps with a dataregion of the subframe #k of the SCC or not, the data region being atime domain region reserved for PDSCH assignment.
 5. A user equipment(UE) for use in a time division duplexing (TDD)-based wirelesscommunication system, the UE comprising: a radio frequency (RF) unit;and a processor operably coupled to the RF unit, wherein the processoris configured to: configure a primary component carrier (PCC) and asecondary component carrier (SCC), wherein the PCC and the SCC havedifferent uplink-downlink (UL-DL) configurations, and for a subframe #k,where the PCC is a special subframe including a downlink pilot time slot(DwPTS), a guard period (GP) and an uplink pilot time slot (UpPTS), andthe SCC is a downlink subframe, perform UE operations under anassumption that a physical downlink shared channel (PDSCH) is notreceived through any part of the subframe #k of the SCC regardless of alength of the DwPTS of the subframe of the PCC.
 6. The UE according toclaim 5, wherein subframe patterns of the PCC and the SCC are givenaccording to UL-DL configurations as follows: Subframe number UL-DLconfiguration 0 1 2 3 4 5 6 7 8 9 0 D S U U U D S U U U 1 D S U U D D SU U D 2 D S U D D D S U D D 3 D S U U U D D D D D 4 D S U U D D D D D D5 D S U D D D D D D D 6 D S U U U D S U U D where D denotes a downlinksubframe, U denotes an uplink subframe and S denotes a special subframe.


7. The UE according to claim 5, wherein the DwPTS of the subframe #k ofthe PCC overlaps with a data region of the subframe #k of the SCC, thedata region being a time domain region reserved for PDSCH assignment. 8.The UE according to claim 5, wherein the UE operations are performedunder an assumption that the PDSCH is not received through any part ofthe subframe #k of the SCC regardless of whether the DwPTS of thesubframe #k of the PCC overlaps with a data region of the subframe #k ofthe SCC or not, the data region being a time domain region reserved forPDSCH assignment.